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THE LABORATORY TESTING OF RAIL FASTENING BY INERTIAL ELECTRODYNAMIC EXCITER METHOD 用惯性电激器法对钢轨紧固进行了室内试验

Akustika Pub Date : 2022-01-01 DOI: 10.36336/akustika20224316

J. Smutný, L. Pazdera, Dušan Janoštík, Radovan Rímský, Iunishchenko Petr

引用次数: 0

RIEMANNIAN MATCHED FIELD PROCESSING 黎曼匹配场处理

Akustika Pub Date : 2022-01-01 DOI: 10.36336/akustika2022442

Quyen Tran Cao

{"title":"RIEMANNIAN MATCHED FIELD PROCESSING","authors":"Quyen Tran Cao","doi":"10.36336/akustika2022442","DOIUrl":"https://doi.org/10.36336/akustika2022442","url":null,"abstract":"As far as underwater source localization is concerned the Matched Field Processing (MFP) is an effective method. Floating ship localization, submarine localization in military section and fish finding in civilization are considered as the main application of MFP. Besides, determining environmental parameters such as sound speed profile, bottom topography and array tilt are also developed. Some methods such as empirical mode decomposition, adaptive MFP, compressive MFP and especially stochastic MFP using Riemannian geometry (RMFP) have been introduced recently in order to increase MFP’s reliability and resolution. It seems that the RMFP is the strongest candidate for the future development of MFP since it is inherited the strong foundation of both MFP and Riemannian Geometry. Surprisingly, not only the nature of curvature of sound wave but also the nature of MFP are exploited in RMFP. The aim of this monograph is introduce RMFP by considering the Riemannian distance instead of Euclidean distance. Two approaches of RMFP construction, i.e., isometric mappings and direct Riemannian distance calculation are introduced. The organization of this monograph is as follows. Two first chapters of this monograph revised the reader about the essential meaning of Gauss Curvature, Geodesic equation, iso-metric mapping in Riemannian Geometry and the state of the art of MFP. Chapter 3 presents Riemannian MFP. Chapter 4 concludes the monograph with discussions about the performance of MFP. This monograph is designed for graduated students, scientists and senior engineers who working in the field of underwater acoustic engineering. We would like to thanks SACLANTC for providing access of SONAR array data. We also express our gratitude to University of Engineering and Technology (VNUH) for partial financial support this monograph. Finally, I deeply express my appreciate to my family, especially my father for their patient and love to me.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70177792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

ACOUSTIC COMFORT IN THE CHURCH OF SANTA MARIA DELLA NEVE, AFTER ITS RENOVATION 圣玛丽亚德拉内夫教堂翻新后的声学舒适度

Akustika Pub Date : 2022-01-01 DOI: 10.36336/akustika20224355

Andrea Vargová, M. Rychtáriková

{"title":"ACOUSTIC COMFORT IN THE CHURCH OF SANTA MARIA DELLA NEVE, AFTER ITS RENOVATION","authors":"Andrea Vargová, M. Rychtáriková","doi":"10.36336/akustika20224355","DOIUrl":"https://doi.org/10.36336/akustika20224355","url":null,"abstract":"The Church of Santa Maria Della Neve (Our Lady of the Snows) on Bratislava Calvary hill was built during the World War II on the site of a chapel from the 18th century and bears the hallmarks of interwar modernism (functionalism). Since 2018 the church underwent a complete renovation of the interior under the leadership of architects Tomáš Bujna and Matúš Gibala. The works included the reconstruction of the interior of the presbytery, the nave of the church, the entrance and service areas, as well as the design and implementation of new furniture. In the church, new plaster and paint were applied to the walls and ceiling. The newly painted white interior provides a sufficient amount of light and thus gives positive and balanced impression for the people present in the church. However, the minimalist style without the use of any sound-absorbing material causes a major problem with speech intelligibility during the ceremonies. Changes in the interior, such as painting the church and removing the sound-absorbing elements on the walls and furniture are responsible for doubling of the reverberation time compared to the original state. The presented article focuses on the search for ways to reduce the reverberation time to the original values by interior elements, which could be accepted in terms of architectural appearance. From the point of view of acoustics, maintaining the diffusion of space is a big challenge here, because by reckless application of additional elements and surfaces with high sound absorption, unpleasant echoes could arise in such a large space. These would probably not impair speech intelligibility dramatically but would for sure interfere with music production. Therefore, auralization was used to find the optimal solution.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70177833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

STOCHASTIC MATCHED FIELD PROCESSING USING DIRECTED RIEMANNIAN DISTANCE 有向黎曼距离随机匹配场处理

Akustika Pub Date : 2021-01-01 DOI: 10.36336/akustika2021403

Tran Cao Quyen

引用次数: 0

BUCKWHEAT HUSK AND EPOXY RESIN BASED COMPOSITES FOR NOISE ABATING 降噪用荞麦壳和环氧树脂基复合材料

Akustika Pub Date : 2021-01-01 DOI: 10.36336/akustika20214018

V. Kozhusko, S. Bukharov, A. Alexiev, R. Iankov

引用次数: 1

REGRESSION ANALYSIS OF THE COEFFICIENTS OF VIBRATION ENERGY LOSSES IN GAS-DISCHARGE SYSTEMS OF POWER PLANTS 电厂气体排放系统振动能量损失系数的回归分析

Akustika Pub Date : 2021-01-01 DOI: 10.36336/akustika202141115

A. Chukarin, A. Fedenko, A. Shashurin, Viktoriia Vasilyeva